Telephone-relay.



JUNE lili. 1898.

UNITED STATES PATENT OFFICE.

EDWARDE. CLEMENT, OF WASHING"ON, DISTRICT OF COLUMBIA.

TELEPHONE-RELAY.

Specification of Letters Patent.

Patented June 19, 1906.

Application iiled June I6, 1898. Serial No. 683,651.

To a/ZZ whom it may concern:

Be itknown lthat'I, EDWARD E. CLEMENT, acitizen ofthe United States, residing at Washington, District of Columbia, have invented al new and useful Improvement in Telephonie Relays, of which the following is present in use are dependent for their operation upon the translation of electrical changes into mechanical changes, which are by a second operation translated again into electrical changes. I have achieved the end of effecting the same result by a-single change-thatis, I translate the current variations in one circuit directly into current variations in a second circuit by a single operation. To effect this, I employ a coil included in the first circuit and a resistance-varying medium in the second, the latter directly acted on by the former without any intermediate mechanism.

It will be seen that while my invention is particularly useful in telephonework-ie., in the relaying of voice-currents-it is equally applicable totelegraphic work, the changes in resistance produced vin the second circuit being prompt and sharp and the relay asa whole 'being simple, cheap, and easily cared for, its liability to get out of order, moreover, being very. small, as there are no adjustments to undergo change, no vsprings to deteriorate, and-no parts that can be injured by exposure to moisture or dust.

My invention includes various details of construction and is-fully set forth in the speci- Jfica-tion and claims hereto appended and illustrated in the accompanying drawings, wherein the same characters refer to thesame parts throughout.

In the drawings, Figures l and 2 are diagrams illustrating the broad principle of my invention. Fig.' 3 is a plan view of a relay constructed in accordance with this principle. Fig. 4 is a section on the line a: of Fig. 3.

Fig. 5is a side view looking in the direction.

in which the arrow points in Fig. 3. Figs. 6, 7, and 8 represent modiications.

Many forms of relay have been suggested and tried in the endeavor to increase the distance through which good clear transmission of speech can be had. In all of these, so far as I know, an electromagnet is employed whose coil is included inthe circuit to be relayed. This magnet exerts a lvarying pull,

.due to the. variations in the current on its circuit, on a diaphragm or armature. The diaphragm or armature in its turn varies the pressure or'intimacy of contact between solid electrodes or granules of carbon or other semilconductor connected into the second circuit.

A single impulse coming over the first circuit, such as would becaused by tapping a telegraph-key, energizes the magnet, which pulls the armature, which decreases(or increases,

as the case may be) the tension on the electrodes in the second circuit, and thus changes the current flowing in the second circuit. This last change will lag behind the original change in the first circuit, however, by reason of the mechanical inertia of the armature and. the electrodes and the magnetic inertia of the iron forming the, core and armature. The time elapsing or the amount of lag will be of no moment, however, even though comparatively large, because there is only one impulse. A musical note causing corresponding current undulations in this first circuit will be accurately reproduced by a telephone-receiver in the second circuit u1iless the armature and spring have a widelydiflerent rate of vibration of their own, because although the changes are periodic they are alsoV simple, and whether one commences on the iirst or the tenth or the hundredth wave crest the rate ofchange is always the same, and consequently the resulting note is the same. vWith speech undulations it is different, however. Here we have a complex change, consisting of a series of fundamental simple periodic changes, upon which are s uperimposed harmonics or overtones ed fm- ]i/ntum'. Obviously the lag is a serious detriment, if not a total deterrent. At the best the undulations -reproduced in the second circuit will be distorted. They will have had some of the little sharp superimposedn'ave crests smoothed oii and perhaps even the rapidly-changing fundamentals will have lost IOO IIO

their perfect characteristics. In order to get l provided on their inner faces with polished rid of this lag, l. employ no armature. a coil or coils connected in the first circuit. make my resistance-varying medium or elec- 5 trodes of magnetic material or of non-niagnetic material rendered susceptible to inagnetic influences for the time, as will be explained, or mix magnetic material therewith, and I place this medium directly within the fieldof the coil or coils. I may polarize the medium by bringing a permanent magnet into proximity thereto, although this is by no means necessary for fair results. In short, I make the resistance-varying medium of the second circuit act. as a portion of the magnetic circuit or core of the magnet in the first, and thus the entire translation is directly performed in one operation, and there are no heavy mechanical moving parts at all to deal with and very little or no magnetic inertia.

Referring'to Fig. 1, A is a permanent magnet, carrying coils c c, which are included in Y the circuit numbered 1. There is alsoineluded in this circuit the secondary winding of an induction-coil I, the primary i of which is in circuit with a battery b and microphone-transmitter T. Between the poles of the magnet A is includ ed a resistance-varying medium M, connected, through contacts fm m, to the primary t of the coil I, the secondary of which is connected into a second circuit, (numbered 2.) There is included in this second circuit a telephone-receiver R. In Fig. 2, A is a permanent magnet. The circlude the same parts as i11.Fig.` 1, and the resist-ancefvarying medium M is similarly included between the poles of the magnet A but in this ease the single coil cis included in the first circuit and directly surrounds the medium M. The/ principle illustrated in these two figures is the same. Undulations caused by the microphone T are`propagated into the circuit 1 through the medium of the, induction-coil I. The coilsc c or c respond to these' und ulationsto alternately strengthen and weaken the field of magnet A. The resistance-varying medium' M being included `in the magnetic circuit rresponds directly to these changes by corresponding changes in the mutual pressure or intimacy of Contact of its component parts and resultant changes in the resistance in circuit with the primary fi', of coilI. The variations 'are finally reproduced in the circuit 2 and affect the receiver R.

I prefer to uselfor the resistancefvarying medium Mgranular material, which I may prepare in several ways hereinafter described, but which'may be simply carbon.

6o A practical embodiment of my invention .is shown in Figs. 3, 4, and 5. Referring to these figures, I) is a hollow spool turned out ofv hard rubberor fiber. Between the iianges vd d of the spoolI wind the coil c. Fitted to' I the ends of the spool are conducting-disks d,

I use l carbon-electrodes e e.

I bore of the spool; but the electrodes are prefcuit 1 and the'circuit 2 are the same and in- The disks d fit the erably of somewhat smaller diameter. The disks I find are best made of very soft iron, and the electrodes are brazed or soldered to them. On one side of each flange of the spool is a contact f, to which one end of the coil c is attached. Radially opposite on each flange is a contactj", connected to one of the disks d. The contacts f f extend slightly beyond the edge of the flanges for a purpose to be presently noticed. Suitably mounted in a base G is the magnet A, its

poles extending upwardly and parallel. Upon 8o the base at opposite sides of the magnet are mounted two pairs of' contactsprings S S and S" S". YThe springs are bent at their upper ends to form slight curvatures approximately hook-shaped and at their lower ends are provided with connecting means, shown as binding-posts p p p p. I insulate, as at df,

one or both disks d.

In assembling'the instrument one disk d is removed, and a quantity of the granular material I shall describe is poured into the bore of the spool until it is almost or quite full. The disk is then replaced and the entire spool slipped between the poles of magnet A, as shown in Figs. 3, 4, and 5. The springs s s s s come into Contact with the contacts fff and automatically complete both circuits, while their slightly-hooked portions retain the spool in place. Y

I make the granular material in several ico ways and have attained good results with each. According to one method I coat irregularly-shaped granules of very soft Swedish iron with shellac and bake, then coat again and again bake. I then mix these 105 granules with about an equal bulk of fine carbon granulated.` The carbon granules may be either spherical or irregular; but the magnetic particles should be irregular. In

lusing the granulated material so composed rio the greater specific gravity of the iron tends to make it sink below the carbon, separating from it. This tendency is counteracted, however, by the lifting effect ofthe poles of.

lmagnet A, As the' tendency is always to x15 shorten the magnetic circuit, there is a balance of forces, and one result of this is that this microphone never packs Accordiner to a second method I make the granules a of magnetic material and. prepare them 12o either by preliminary coating with carbonaceous material and baking or by a system of flashing, 'such as incandescent-light filaments are subjected to. v-I may use also for the granular material carbon .of a suflicient hardi 25 ness and high enough quality to carry a considerable current without1 deterioration. In this case the effect is to render the granules carrying the current susceptible to magnetic influence, the current in passingthroughthe 13o granules creating a field around each granule which cooperates withthe external iield and causes any chan es in the latter to tend to move the granu es bodily, just as if they were of magnetic material.

Fig. 6 shows the same form of coil and magnet as Figs. 3, 4, and 5, but se arate buttons of magnetic material coate with carbon or a similar semiconductor, substituted for the granular material.

In Fig. 7 I show a double coil on the poles of the magnet A and an exhausted glass capsule between the poles containing the electrodes and the granular material. q is the nipple, where the capsule is sealed, and g g are the terminals ofthe electrodes sealed into the glass. I may likewise seal the magnetpoles directly into the glass.

Fig. 8 shows an alternative position oi the relay, where the magnet-poles and the spool are arranged horizontally.

I am aware that it is not broadly new -to use magnetic material for the resistancevarying medium in a microphone; but I believe I am the first to so place such a resistance-varying medium as to make it part of a magnetic circuit or a core and then to vary the strength of the circuit or effect on. the core proportionately to the variations in an electric circuit, whereby the resistance of the resistance-varying medium is varied to repro duce the variations in va second electric circuit.

Having described my invention, what I claim as my own, and desire to secure by Letters Patent of the United States, is-

l. Ina relay, a magnetic circuit composed in part of a divided variable-resistance niediuni, two electric circuits, means connected in one electric circuit to produce changes in the magnetic circuit, said variable-resistance medium being connected into the second.

electric circuit, whereby electrical changes in the first circuit are translated -into magnetic changes in the relay, and directly into electrical changes in the second circuit.

2. In a relay, a coil connected to a trans-l mitting-circuit, of a magnetic variable-resistance medium forming part of a ,second circuit, said resistance-varying medium being arranged with relation to the said coil so as to be directly affected thereby without the interposition, of a diaphragm or other mechanicaily-moving parts, and in exact' cuit. electrodesarranged within the bore ofsaid spool and connected in a receiving-circuit, and resistance-varying material be tween said electrodes, substantially as def' electrodes and resistance-varying medium,

substantially as described. v

6. In a relay, a permanent magnet, a coii on the magnet included in a first or transrnitting circuit, electrodes and granular ma terial arranged in close proximity to and.

adapted to be directly affected by said coil, and included in a second or receiving circuit together with a source of current; said granular material being susceptible to magnetic iniluence, substantially as described.

7. In a relay, a coil included in a iirst or transmitting circuit, electrodes and granular material arranged in close proximity to and adapted to be directly aiected by said coil, and included in a second or receiving circuit, together with a source of current; said gran* ular material being susceptible to magnetic influence, substantially as described.

8. Ina relay, a resistance medium of carbon granulate incorporated .with iron, two electric circuits, means connected in one electric circuit to produce changes in the carbon iron granulate, said granulate bei connected into the second electric circuif'.. whereby electrical changes in then'irst circuit are translated intoniagnetic changes in the relay, and directly into electrical changes in the second circuit, substantially as de scribed.

' 9. A relay for telephones or other electric apparatus in which an 4undulating current used, said relay coneisting of a magnetizingcoil adapted Jfor connection with the trans mitting-circuit, electrodes located within thel coil, particles of magnetizable material located between said electrodes and adapted to form a conducting-path from one electrode to the other, and a relay-circuit in which said electrodes are included, substantially as described.

10..- A relay or repeater, comprising a coil orelectromagnet, and a granular resistancevarying medium, responsive in itself to mag- IOL netic variation, exposed to the field of said coil or electromagnet, and included in a relaying or repeating. circuit, substantially as described.

11'. Arelay or repeater for use between twocircuits, comprising an electromagnet or coil included in one circuit, two electrodes included in the other circuit, which forms relaying or repeating circuit, and a magncl'irl granular resistance varying medium nrranged between said electrodes and expirer-i to the field ol' said electromagnet or coil, suty stantially as described.

4 5 particles.

12. A relay or repeater for use between tWo circuits, comprising an electromagnet or c oilincludedin' one circuit, and a granular resistance-varying medium made up of pair- 5l ticles of magnetic material coated Withaf non-oxidizing material, exposed to the fieldof said electroinagnet or`coil, and included in the Vother circuit, substantially as described.

1o l'13'. A relay or repeater for use between two circuits, comprising an electromagnet or v coil included in one circuit, and-a granular resistance-varying. medium made up of particles of iron or steel, coated W1th carbon, eX-

[5 posed totheliield ofsaid electromagnet or coil, andincluded in-the other circuit, substantially as described. y 14. In' atelephone system,the` combination of a line-circuit, an electromagnet or -coil '2o included therein, and a magnetic granular .resistance-varying medium included in a relaying or repeating circuit, with a fresh source of electricity therein, substantially as described.

15.- In aftelephone system, the combination of a line-circuit, an elcctromagnet or coil included therein, aA magnetic `granular resistance ,-varying medium included in a'relaying or repeating circuit, with a fresh source of electricity; therein, an induction-coil having lits primary included in the .relaying or repeating circuit,-and its secondary connected to a receiver, or to the next section of the linevcircuit;substantially,as described.

if. 16'. Ina telephone system, the combinaa telephone system,I thev combination, with a transmitting-circuit and a receiv ing-circuit, of a repeater comprising an elec-4 -tromagnet the coi s of which are :connected to at e :transmitting i circuit,l magnetizable particles of metal. arranged Within theiiniiuyence of said coils, a local circuit in which said .particles are included, and an induction-coil :theprimarywinding of .which is included in i said circuitl andthe secondary ,Winding of which is connected to the receiving-circuit.

18. A telephone-repeater com rising an induction-coil, the secondary o which, is`- adapted to be connected to a receiving-circuit, a local circuit includinl the primary Windingfof said coil, a chain o :magnetizable metal particles,.in said local circuit, and a magnet-coil'arran ed toiniuence lthecoher-v ence oli-,said partie es and .-ad'apfted to be connected 1n a transmitting-circuit.

. seance 19. A telephone-repeater comprising an induction -`coil, the secondary winding 'of y l which is adapted to be connected to areceiving-circuit, a local circuit includin the primary Winding of said coil, a chai-n o -magnet- 'izable metal particles in said local circuit, a soft-iron core vadjacent to. said particles, a permanent magnet adjacent to said soft-iron core, and a magnet-coil surrounding said core and adapted to be connected to-a transmitting-circuit. y

21. A telephone-repeater/ comprising an induction-coil the secondary Winding of which is adapted to be connected to a rece'iving-circuit, a local circuit including the` primary Winding of said coil, a permanent magnet, a pair of soft-iron cores-each having an end adjacent to said magnet, the opposite ends of saidcores being arran ed 1n proximity to one another, a group o -magnetizable 'metal particles adjacent to said proximate ends and included in the local circuit, and

Icoils upon saidicores adapted to be connected to a transmitting-circuit.

22. A telephone-repeater comprising anv induction coil, the secondary winding of Which is ladapted to be connected to a receiving-circuit, a local circuit. including the primarywinding of said coil, a chain of :magnetizable metal particles in said local circuit, a soft-'iron.coreadjacent to said particles, a -permanent magnet adjacent to said soft-iron core, and a ma net-coil 4surrounding-said coreand adapte to be connected to a-transmitting-circuit, and a' box arranged to vhold the particles adjacent to the core.

23. In a telephone-repeater, a" group 'of magnetizjable metal particles, a-transrnittingcircuit,means operated byfthe current 1n said circuit for varyingthe coherence ofsaid particles, 'a circuit in -which saidl articles are included, and a'receiver arrange tobe operated by the current in said latter circuit.

24.. In a telephone-repeater, a group of magnetizable metal articles having va coat- IOO IIO

ing of carbon in coml ination with a local cir'- cuit in' which said particles are included, and meansa for varying the coherence of.,sa1d\par ticles..

" f25. In a i:telephone -repeater, aecoherer f m'gits polesadjacent-tosaidfcores.

. 2. In a relay, a resistance medium of car-A bon .granuiate incorporated with iron, a

transmitting apparatus adapted tok produce electncal changes in intervening media, and

thereby to affectt'he carbon-iron mixture to alter its resistance, and a receiving-circuit including the resistance medium, whereby "..changing electrical conditionsproduced `by vthe transmitting apparatus produce changes vro ofresistance'in the .relay and thereby produce electrical changes in the receiving-circuit.

27. Anelectrical relay comprising fixed non-vibratory electrodes, a mixture of iron and carbon between said electrodes, and means for confining the same.

28. An electrical relay comprising` fixed non-vibratory electrodesand va mixture of l-finely-divided carbon, and iron, therebetween.

29. An electrical relay comprising fixed non-vibratory electrodes and amixture of carbon and finelydivided iron therebetween.

30. In an electrical transmission system, a transmitting apparatus, a receiving apparatus, and a sensitive resistance device conv nlected with the latter comprising as its essen- 'tial feature a mixture of carbon and iron, "with means whereby the transmitting apparatus may act electrically through intervening media to affect the resistance device to alter its condition, and the changel thus pro-l duced may affect the receiving apparatus.

31. Anelectrical relay comprising as its es- 'sentialfeature a semiconductor, as carbon, and a metal, as iron, arranged to cooperate Y in response to electrical changes produced in their vicinity to alter their joint resistance, -witli a circuit including said materials and and circuit connections therefor relatively fixed during operation of the relay.

35. In an electrical relay, relatively fixed terminal electrodes of iron, and a semiconductor interposed between said electrodes and bridging across the same l 36. An electrical relay comprising relatively fixed electrodes, a mixture of iron and carbon between said electrodes, and means for confining the same.

437'. An electrical relay comprising relatively fixed electrodes and a mixture of finelyl 4divided carbon, and iron, therebetween.

38. An electrical relay comprising relatively fixed electrodes and a mixture of car-v bon andfinely-divided iron therebetween.

39. In an electrical relay device, a metallic resistanceniedium magnetically responsive, a circuit, means to develop a variable magnetic field in accordance with current change in said circuit, and electrical connec` ions through said metallic medium, all so arranged that the said metallic medium may be affected magnetically to vproduce changes within itself and in its circuit, corresponding to the electrical changes in the first circuit.

40. In a relay system, a transmitting-circuit and means to produce electrical changes therein, means responding to said changes to produce a varying magnetic field, a sensitive resistance medium exposed to said magnetic field and directly respon ding to changes therein by changes in itself, together with a second circuit connected with said sensitive resistance medium.

41. In a relay system, a transmitting-circuit and means to produce changes therein, means connected to said circuit to produce and tovary a magneticf field in response to said changes, a sensitive resistance medium directly responsive to said magnetic variations to produce changes in its own character or condition, and a second circuit connected to said sensitive resistance medium to be affected thereby. y

42. A relay system comprising means for producing initial electrical or electromagnetic effects, a sensitive resistance medium responding directly thereto by changes in its own character or condition, and means affected by the changes in said resistance medium to produce secondary electrical or electromagnetic effects corresponding to the initial ehects.

. 43. A telephonic relay system comprising means to produce initial electrical circuitchan es, a sensitive resistance medium respon ing directly thereto by changes in its Vown condition, .and means to render said changes effective electrically or electromagnetically in a second circuit. l

44. As a means for reproducing the variations of current in an electric circuit, an electromagnet Subj ect to the infiuence of said variations, and a sen sitive resist-ance medium of the general character described located in the field of force of the said magnet.-

45. As a means for reproducing current variations in an electric circuit, an electromagnet subject to the influence of said variations, a sensitive resistance medium located in the field of force of the said magnet, anda receiving apparatus in circuit with the sensitive resistance medium.

46. The combination of a telephonie transmitting-circuit, a telephone-receiver, a circuit including the latter, and an inclosed sensitive resistance medium included in the latter circuit, and an electroinagnet traversed IOO IIO

by electric currents due to the eiiects oitl the transmitting-circuit,y and acting upon the sensitive resistance medium, substantially as described. y 47. The combination vwith a telephonie transmittingcircuit, an electromagnet ineluded therein, a telephonic receiving-circuit having an inclosed sensitive resistance medium inserted therein, the sensitive resist-- to ance medium and the electiomagnet occupying such relative positions that a portion at least of the lilies of torce from the electromagnet act upon the sensitive resistance medium,

48. vrihe combination with a telephonie I5' transmitting-circuit and an electrom'agnet included therein, ot a' telephonie receiving-circuit and a resistance apparatus included therein, said resistance apparatus comprising a completely-inclosed chamber and a sensizo tive resistance material therein, the resistance apparatus and magnet occupying such relative positions that a portion at least of the lines of i'orce from the magnet will act upon the sensitive resistance material.

49. The combination With a telephonic transmitting-circuit and an electromagnet included therein, of a telephonic receiving-circuit and a resistance apparatusv included therein, said resistance apparatus comprising 3o an exhausted chamber and a sensitive resistance medium inclosed therein, said resistance apparatus and magnet occupying such relative positions that some or all of the lines of force from the magnet will act upon the sen- 3 5 sitive in'closed medium.'

50. The combination With a telephonic transmitting-circuit and an electromagnet included therein, of a telephonie receivingcircuit and a resistance apparatus included 4o tlerein, said resistance apparatus comprising a chamber -exhausted of air and a sensitive resistance medium inclosed therein, said resistance apparatus aiid"said magnetoccupying such relative positions that a portion at i 5 least ot the lines of torce from the magnet will act upon the sensitive resistance medium.

5l. In an apparatus ofthe class described, a localcircuit having a portion thereof formed of comminuted magnetic particles in rela- 5o -tively loose contact, a normal magnetic flux through such particles, and r,a Wind ing around said particles adapted to be energized by received impulses. l 'f Y' 52. In apparatus of the *class described, a

conductor of relatively liigh resistance composedoi amass of comminuted'magneticparticles in relatively loose contact, means for setting up a normal magnetic lux therewthrough, and a Winding around said mass 6o adapted to be energized by high-frequency oscillations, substantiallyas described.

53. In apparatus or' theclassdescribed a -rnass of comminuted material, ypermcable Ato magnetic llines of force, means for'vsetting `up 6 5 a normal magnetic flux` therethroughJ ar'iojcal therethrough, and means for varying the l circuit embracing such mass, and a Winding around such mass adapted to be energized` by high-frequency impulses.

54. In an apparatus of the class described, a p mass of magnetic particles' in relatively loose fgfo contact, means for lsetting up a magnetic nur;

magnetic permeability of such mass consist ing ina winding around such mass adapted zI' to be energized by received impulses. f v

55. In apparatus of the class described contact of variable resistance having its members of magnetic material, a normal-magnetic flux therethrough, and a Winding around said members adapted to be energized by highfre- 8o quency impulsesl i Y 56. In apparatus of the class described a variable-resistance contact composed ot mem. bers of magnetic material, a normal magnetic luX therethrough, and means for altering the, 8 5 permeability of such members by means ot a Winding adapted to be energized by hightre c quency impulses.

57, In apparatus of the class described'a magnetic resistance variable in-a functionoi 9o the intensity of magnetic flux therethrough, and a winding for received impulses adapted when energized/to va'ry the normal magnetic `flux.. 58. In an apparatus of the class described, 95 a mass of comminuted 'particles embracing magnetic material, a normal magnetic linx therethrough, a local circuit embracing suchI mass as a resistance, and a Winding around. such mass energized by received impulses. roo

59. In an apparatus of the class described,

a mass of comminuted-particles embracing magnetic material, and forming part oa-local circuit, a normal magnetic nur; therethrough, and a winding around suoli mass energized by received impulses.

60. A variable conta ct composed of members permeable to magnetic lines of torce, a normal magnetic Vflux therethrough, and a Winding energized by high -frequency im,- rio pulses and adapted to'vary the permeability of such members` 61. In apparatus tor transmitting messages, means tor transforming electrical undulations into qualitatively-corresponding mag -l r i5 netic undulations Within a supplemental magnetic field, producing kthereby qualitativelycorresponding resultant magnetic product -undulations, Aand causing qualitativ'ely--cpij-` #responding mechanical vibrations quanti- 12o tatively proportionate tothe resuitant mag netic product undulations, thereby quantita- 4 7 tively enhancing 'the mechanical result while preserving therein thecharacteristic quality of the original electrical undulations. y 1 2 5 62. In apparatus for transmitting4-messages, a suppiemental"magnetic iield.,and, ,n means operating within said field Jfor tra ,s-`

`forming electrical undulations into qualitatively'- corresponding magneticundulations, 13o

ses-,763

'producing thereby qualitatively-corresponding resultant magnetic product undula-tions, means for establishing and maintaining a symmetrical relation between the forces oi the-supplemental iield and the electricallyinduced magnetism respectively, and transforming the resultant magnetic product undulations into qualitatively-corresponding mechanical vibrations or changes.

63. In apparatus for transmitting telephonic messages, mea-ns for transforming electrical undulations into ualitatively-corresponding magnetic undu ations within a supplemental magnetic field, andfor producing by means of the said resultant magnetic product undulations rectilinear mechanical vibrations quantitatively proportionate' and qualitatively corresponding to the resultant magnetic-product undulations ,and means res onding to the qualitatively-corresponding e ectrical undulations caused thereby.

64. An electrical relay comprising a mag.

netic field, means for transforming electrical undulations into corres onding magnetic undulations within said ilield,fand a magnetic variable-resistance medium responsive to the resultant magnetic effects thus produced.

65. A telephone f relay comprising a coil connected in one circuit inclosing a magnetic variable-resistance device connected in a second circuit.

66. In a relay, a magnetic circuit composed in part of a non-solid or substantially luent variable-resistance medium, two electric circuits, means connected in one electric circuit to produce changes in the magnetic circuit,

said variable-resistance medium being connected into the second electric circuit, whereby electrical changesv in the first circuit are translated into magnetic changes in the relay, and directly into electrical changes in the second circuit.

67. In a relay, a coil connected to a transmitting-circuit, of a non-,solid variablere sistance medium forming part of a second circuit, said resistance-varying medium being arranged with relation to the said coil so as to be directly affected thereby without the in- `terposition' of a diaphragm or other mechanically-movable parts, and in exact accordance with electrical changes in the first circuit, whereby said changes are reproduced in the second circuit. l

68. in a relay, a magnetic circuit including a variable-resistance medium whose ultimate constituent particles are movable with respect to eachother, two electric circuits, means` connectedl in one electric circuit to producechanges in the magnetic circuit, said 

